PUBLIC HEALTH ADVISORY Seizures In Patients Without Seizure Disorder Being Treated With Tiagabine (GABITRIL)

The Food and Drug Administration (FDA) issued a public health advisory on Feb. 18, 2005 to announce that a Bolded Warning will be added to the professional product labeling, or package insert, of tiagabine (GABITRIL). The new label will warn of seizures in patients without a previous seizure disorder who are being treated with this drug.

Tiagabine was approved by the FDA in 1997 for patients 12 years of age and older as adjunctive therapy (use in addition to other medications) for partial seizures. The drug is manufactured by Cephalon, Inc. of West Chester, PA.

The FDA is aware of seizures associated with the use of tiagabine in more than 30 patients who were prescribed the drug for conditions other than partial seizures such as psychiatric illnesses like bipolar disorder. Because the system for reporting adverse drug reactions is voluntary, the number of reports of adverse reactions that the FDA receives once a drug has been marketed is only a fraction of the actual number of reactions that have occurred. The FDA estimates that only from one in ten to one in 100 serious adverse reactions are reported.

Typically, the seizures have occurred soon after the start of treatment with tiagabine or soon after an increase in dose, although some patients experienced seizures after several months of treatment. Some seizures have occurred at very low doses compared to the doses approved for use in patients with partial seizure. Although most of the patients in whom seizures occurred were also taking other medications that may infrequently cause seizures, the temporal relationship to the initiation of treatment with tiagabine or to dose increases in many cases, as well as the number of patients reporting seizures, strongly suggests that the seizures were primarily caused by tiagabine.

Prescribing tiagabine for a use that it is not FDA-approved is referred to as off-label prescribing. Some of the worst drug disasters in U.S. history in terms of needless injuries and deaths have involved off-label prescribing. One such example is the prescribing of hormone replacement therapy to prevent heart disease and Alzheimer’s disease in postmenopausal women (see Worst Pills, Best Pills News September 2002). Worse yet, the patient receiving a drug for an off-label use is an unwitting guinea pig in a large uncontrolled experiment in which no one is collecting results.

In addition to the occurrence of isolated seizures, the FDA has received several reports of status epilepticus in patients without a seizure disorder. Status epilepticus is a particularly dangerous event in which patients have continuous seizures without regaining consciousness between seizures. In some cases, physicians have continued to treat with tiagabine or actually increased the dose in patients in whom seizures occurred.

What You Can Do

DO NOT stop taking tiagabine without talking to your physician.

You should not be taking tiagabine for any use other than treatment of partial seizure. Tiagabine has not been shown to be safe and effective for any use other than treatment of partial seizure.

If you or a family member experiences an adverse effect from tiagabine, or any other drug, you can report it to the FDA’s MedWatch program.

Online: www.fda.gov/medwatch/ 
Phone: 1-800-FDA-1088
Fax: 1-800-332-0178